Multiple myeloma comprises 1% of all cancers, and accounts for 10% of haematological malignancies. The median age at diagnosis is 60-65 years; <2% of myeloma patients are <40 years old at diagnosis.
The results of current treatments available for patients with symptomatic multiple myeloma are disappointing. The median survival is <3 years and the prospects for survival at 10 years are poor with conventional chemotherapy. Initial treatment with intermittent cycles of melphalan and prednisolone has a median duration of response of only twenty-four months and median survival of approximately three years. Consistently in clinical trials less than 10% of patients survive more than 10 years from diagnosis and there are very few long-term survivors. A number of combination chemotherapy regimens have been used and although higher response rates have been demonstrated there has been little impact on the duration of survival. High dose therapy followed by autologous bone marrow or peripheral blood stem cell rescue (AutoPBSCT) increases the response rate, disease free survival and overall survival but the majority of patients relapse within five years. The origin of cells causing relapse in these patients is not known but must arise either from the re-infusion of tumour cells contaminating autologous material or from inadequate elimination of disease by the conditioning regimen or a combination of the two. Increased tumour reduction in vivo could in theory be possible by further increasing the conditioning therapy. This has been tested in a number of studies using additional chemotherapeutic agents or with the addition of external beam or high-voltage total body radiotherapy as total body irradiation. However, intensification of conditioning therapy has been associated with significant increase in toxicity.
Frequently used first line conventional chemotherapy are combinations of up to 4 cytotoxic drugs such as doxorubicin, carmustine, cyclophosphamide, dexamethasone, etoposide, melphalan, (methyl)prednisolone, vincristine and idarubicin all of which are supplemented with bone protecting agents like bisphosphonates (Clodronate etc). However this treatment results rarely in complete remissions (CR) and long term remissions are rare.
Therefore, autologous stem cell transplantation (ASCT) was introduced as second line treatment of symptomatic MM patients. Various conditioning regimens such as high dose melphalan (HDM), HDM in combination with total body irradiation (TBI), HDM in combination with busulphan, low dose melphalan in combination with cyclophosphamide followed by TBI and HDM in combination with etoposide followed by TBI were clinically investigated.
HDM (200 mg/m2) followed by ASCT has substantially increased the frequency of remission and has prolonged progression free survival (PFS) and overall survival (OS) being established now as the standard of care for treatment of symptomatic MM (Terpos E. et al., Expert Opin. Pharmacother., 2005, 6 (7): 1127-1142).
As third line setting thalidomide, bortezomib and others are used to further improve treatment. Furthermore, in a variety of studies experimental drugs such as anti-angiogenic compounds, histone deacetylase inhibitors, metalloprotease inhibitors, farnesyltransferase inhibitors, heat shock protein inhibitors and BCL2 antisense oligonucleotides are being evaluated.
The toxicity associated with further dose escalation has led to the development of tandem autologous transplants which allow the delivery of treatment intensification with less toxicity than the equivalent treatment in a single transplant event. The role of tandem stem cell transplantation remains undecided.
A feature of disease progression in myeloma is the appearance of chemotherapy resistance, in part due to the expression of the multiple-drug resistance mediated by p-glycoprotein, multi-drug resistance related protein or the major vault protein. New treatment strategies directed at the malignant cell population need to be developed, particularly that destroy malignant cells by mechanisms different to systemic chemotherapy. Therapeutic strategies that exploit the inherent radiosensitivity of malignant plasma cells while reducing the non-specific toxicity of external beam irradiation have been tested; these include total marrow irradiation in combination with busulphan and cyclophosphamide or targeted radiotherapy using radiolabelled bone seeking agents. Total marrow irradiation is technically difficult and in practice is a form of TBI with modified organ shielding, 90% of lung and liver were shielded (9 Gy in 6 fractions) and separate electron beam treatment given to rib areas protected from TBI. Overall response rates were good with 39/89 (44%) patients achieving CR and 50/89 (56%) a PR. In patients with de novo myeloma the CR rate was higher at 48%. However toxicity to non-haematopoietic tissues were high with 68/89 (76%) experiencing gastrointestinal toxicity grade III-IV. Durations of stay in hospital were also longer than for high dose melphalan due to the long (12 day) pre-treatment before stem cell infusion.
A number of radioimmunoconjugates (RIC) using monoclonal antibodies selective for haematopoietic antigens such as CD45, CD33, CD20, CD19 and CD66 have been the subject of investigations for bone marrow conditioning before transplantation in haematological malignancies such as acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) and transformed myelodysplasia (MDS), (Matthews D. et al., Blood, 1999, 94: 1237-1247; Jurcic J G, Cancer Biother Radiopharm., 2000, 15: 319-326; Bunjes D. et al., Blood, 2001, 98: 565-572). RIC was applied in addition to standard conditioning regimens to evaluate their efficacy in a clinical setting. However, most of these radioimmunoconjugates show uptake in non-haematopoietic organs such as the liver and kidneys. The cause of this non-target uptake of radioimmunoconjugate is multifactoral and includes specific and non-specific uptake and instability of the immunoconjugate in vivo. This non-haematopoietic uptake limits the amount of immunoconjugate that can be administered, thus limiting their potential as targeting agents, reducing effective radiation dose delivered to the bone marrow. Consequently, despite a promising targeting effect on the tumor mass and bone marrow, the applied RICs show severe dose limiting toxicity in liver, lung and kidneys. This dose limiting toxicity may be due to the selectivity of the antibodies used and/or the stability of the attached radiolabel (e.g as observed using the 188Re labelled reduced molecule of anti-CD66 MAb studied by Bunjes et al.).
Thus, there is a need to provide further improved therapeutic procedures for the treatment of haematological disorders.
Unexpectedly, we have found that targeted radioimmunotherapy in bone marrow conditioning using a RIC consisting of monoclonal antibody BW 250/183 selective for CD66 (anti-CD66 MAb) radiolabelled with 90Y leads to complete remission in several cases of multiple myeloma.
A subject matter of the present application is the use of a radioimmuno-conjugate (RIC) for the manufacture of a medicament for the administration in the therapy of a haematological malignant disorder, particularly in a human patient, wherein the RIC comprises a CD66-binding component and a radionuclide.
The haematological malignant disorder may be a leukemia, which may be selected from multiple myeloma (MM), acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myeloid leukemia (CML), chronic lymphocytic leukemia (CLL) and lymphoma. More particularly, the haematological malignant disorder is multiple myeloma.
The therapy may comprise administration of radionucleotides suitable for imaging and/or therapeutic irradiation of bone marrow as well as tumor cells. The RIC administration is preferably a conditioning regimen in combination with further therapeutic measures as explained in detail below.
The radionuclide of the RIC may be a therapeutically effective radionuclide, i.e. a radionuclide which is suitable for the treatment of haematological malignant disorders by irradiation. For example, the therapeutically effective radionuclide may be yttrium-90 (90Y), iodine-131 (131I), samarium-153 (153Sm), holmium-166 (166Ho) rhenium-186 (186Re), rhenium-188 (188Re) or another β- or β/γ-emitting radionuclide, or may be an α-emitter such as astatine-211 (211At), bismuth-212 (212Bi), bismuth-213 (213Bi) or actinium-225 (225Ac).
The radionuclide of the RIC may also be an imaging radionuclide, i.e. a radionuclide which is suitable for monitoring and/or determining pharmacokinetics of the RIC. For example, the imaging radionuclide may be indium-111 (111In), iodine-131 (131I) or techneticum-99m (99mTc).
In an especially preferred embodiment the invention encompasses determining the therapeutically effective dose of a therapeutic RIC prior to administration. This determination may be carried out individually for a subject to be treated, or for a group of subjects, e.g. based on the severity or progression of the disease. For example, the invention may comprise the administration of an RIC comprising an imaging radionuclide and a subsequent administration of a RIC comprising a therapeutically effective radionuclide. By means of first administering an imaging RIC, the effective dose of the subsequently administered therapeutic RIC may be individually determined and/or adjusted for a respective subject, e.g. a human patient. In this embodiment, the CD66-binding component of the imaging RIC and the therapeutic RIC is preferably identical, at least with respect to the CD66-binding specificity and/or affinity.
It should be noted, however, that administration of an imaging RIC prior to administration of a therapeutic RIC might not be necessary, if sufficient patient data has been collected, e.g. in a database, to determine a therapeutically active amount of the RIC. Thus, a further preferred embodiment of the invention comprises determining a therapeutically effective dose of an RIC by evaluating pre-existing data, e.g. from a database.
The CD66-binding component is preferably a polypeptide comprising at least one antibody binding domain, for example an antibody, particularly a monoclonal antibody, a chimeric antibody, a humanized antibody, a recombinant antibody, such as a single chain antibody or fragment thereof, e.g. proteolytic antibody fragments such as Fab-, Fab′- or F(ab)2-fragments or recombinant antibody fragments, such as single chain Fv-fragments.
The CD66-binding component may also be a fusion polypeptide comprising at least one antibody binding domain and a further domain, e.g. an effector domain such as an enzyme or cytokine. Alternatively, the CD66-binding molecule may be an ankyrin or a scaffold polypeptide.
In a preferred embodiment, the CD66-binding component selectively binds to the human CD66 antigen or an epitope thereof, e.g. CD66a, b, c, d or e. In an especially preferred embodiment the CD66-binding component is the BW250/183 antibody. Murine, humanized and recombinant forms of this antibody are described in EP-A-0 388 914, EP-A-0 585 570 and EP-A-0 972 528, which are herein incorporated by reference.
The radionuclide is preferably linked to the CD66-binding component via a chelating agent, with the linkage preferably being a covalent linkage. More preferably the radionuclide is linked to the CD66-binding component via a structure of the formula[(chelating agent)-(R1)p—(R2—R3)n]m-(CD66-binding component)    wherein n is 0 or 1,    m is 1 to 15,    p is 0 or 1,
R1 and R3 are independently selected from the group consisting of —NHCSNH—, —NHCONH—, —NHCOCH2S—, —S—S—, —NH—NH—, —NH—, —S—, —CONHNH—, —SCH2CH2COONH—, —SCH2CH2SO2—, —SCH2CH2SO2NH—, —CONH—, —O—CH2CH2O—, —CO—, —COO—, —NH—O—, —CONHO—, —S—(CH2)3C(NH) NH—, —NH—COO—, —O— and

R2 is selected from the group consisting of C1-C18 alkylen, branched C1-C18, —CH2—C6H10—, p-alkylphenylene, p-phenylene, m-phenylene, p-alkyloxyphenylene, naphthylene, —[CH2CH2O]x—, —[CH2CH2SOCH2CH2]x, —[CH2CH2SO2CH2CH2]x—, or —[NHCHR4CO]y—, wherein x is 1 to 200, y is 1 to 20, and wherein R4 is selected from the group consisting of H—, Me-, HSCH2—, isopropyl, but-2-yl, CH3SCH2CH2—, benzyl, 1H-indol-3-yl-methyl, HOCH2—, HOOCCH2—, CH3CH(OH)—, HOOCCH2CH2—, 4-hydroxybenzyl, H2NCOCH2—, H2NCOCH2CH2—, 2-guanidinoethyl, 1H-imidazol-5-yl-methyl and 2-methylprop-1-yl.
For example, the chelating agent may be selected from the group consisting of diethylenetriaminepentaacetic acid (DTPA), 1,4,7,10-tetraazacyclododecane-N,N″,N″,N′″-tetraacetic acid (DOTA), 1,4,8,11-tetraazacyclotetradecane-N,N′,N″,N′″-tetraacetic acid (TETA), 1,4,7-triazonane-N,N′,N″-triacetic acid (NOTA), 2,2′-(2-(((1S,2S)-2-(bis (carboxymethyl)amino)cyclohexyl)-(carboxymethyl)amino)ethylazanediyl) diacetic acid (cyclohexano-DTPA), 2,2′-(2-(((1R,2R)-2-(bis(carboxymethyl)amino)cyclohexyl)-(carboxymethyl)amino)ethylazanediyl)diacetic acid, 2,2′-(2-(((1S,2R)-2-(bis(carboxymethyl)amino)cyclohexyl)-(carboxymethyl)amino)ethylazanediyl)diacetic acid, 2,2′-(2-(((1R,2S)-2-(bis(carboxymethyl)amino)cyclohexyl)-(carboxymethyl)amino)ethylazanediyl)diacetic acid, 2,2′,2″, 2′″-(2,2′-(1S,2S)-cyclohexane-1,2-diylbis((carboxymethyl)azanediyl)bis(ethane-2,1-diyl))bis(azanetriyl)tetraacetic acid, 2,2′,2″, 2′″-(2,2′-(1S,2R)-cyclohexane-1,2-diylbis((carboxymethyl)azanediyl)bis(ethane-2,1-diyl))bis(azanetriyl) tetraacetic acid, (1R)-1-benzyl-diethylenetriaminepentaacetic acid, (1S)-1-benzyl-diethylenetriaminepentaacetic acid, (2R)-2-benzyl-diethylenetriaminepentaacetic acid, (2S)-2-benzyl-diethylenetriaminepentaacetic acid, (2R)-2-benzyl-(3R)-3-methyl-DTPA, (2R)-2-benzyl-(3S)-3-methyl-DTPA, (2S)-2-benzyl-(3S)-3-methyl-DTPA, (2S)-2-benzyl-(3R)-3-methyl-DTPA, (2R)-2-benzyl-(4R)-4-methyl-DTPA, (2R)-2-benzyl-(4S)-4-methyl-DTPA, (2S)-2-benzyl-(4S)-4-methyl-DTPA, (2S)-2-benzyl-(4R)-4-methyl-DTPA, (1R)-1-benzyl-(3R)-3-methyl-DTPA, (1R)-1-benzyl-(3S)-3-methyl-DTPA, (1S)-1-benzyl-(3S)-3-methyl-DTPA, (1S)-1-benzyl-(3R)-3-methyl-DTPA, (1R)-1-benzyl-(4R)-4-methyl-DTPA, (1R)-1-benzyl-(4S)-4-methyl-DTPA, (1S)-1-benzyl-(4S)-4-methyl-DTPA, (1S)-1-benzyl-(4R)-4-methyl-DTPA, 2,2′-((1R,2R)-2-(((R)-2-(bis(carboxymethyl)amino)-3-phenylpropyl)(carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, 2,2′-((1S,2S)-2-(((S)-2-(bis(carboxymethy(amino)-3-phenylpropyl) (carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, 2,2′-((1R,2R)-2-(((S)-2-(bis(carboxymethyl)amino)-3-phenylpropyl)(carboxymethyl)amino) cyclohexylazanediyl)diacetic acid, 2,2′-((1S,2S)-2-(((R)-2-(bis(carboxymethyl)amino)-3-phenylpropyl)(carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, 2,2′-((1R,2S)-2-(((R)-2-(bis(carboxymethyl)amino)-3-phenylpropyl) (carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, 2,2′-((1S,2R)-2-(((S)-2-(bis(carboxymethyl)amino)-3-phenylpropyl)(carboxymethyl)amino) cyclohexylazanediyl)diacetic acid, 2,2′-((1S,2R)-2-(((R)-2-(bis(carboxymethyl) amino)-3-phenylpropyl)(carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, 2,2′-((1R,2S)-2-(((S)-2-(bis(carboxymethyl)amino)-3-phenylpropyl) (carboxymethyl)amino)cyclohexylazanediyl)diacetic acid, (2S)-2-benzyl-1,4,7,10-tetraazacyclododecane-N,N′,N″,N′″-tetraacetic acid, (2R)-2-benzyl-1,4,7,10-tetraazacyclododecane-N,N′,N′,N′″-tetraacetic acid, 6-benzyl-1,4,8,11-tetraazacyclotetradecane-N,N′,N″,N′″-tetraacetic acid, 2-benzyl-1,4,7-triazonane-N,N′,N″-triacetic acid, or a derivative thereof. In an especially preferred embodiment, isothiocyanato-benzyl-3-methyl-diethylenetriaminepentaacetic acid (ITC-2B3M-DTPA) is used as the chelating agent.
The administration of the therapeutic RIC for the treatment of human patients is preferably in a dose of ≧about 10 MBq/kg body weight (bw), preferably of ≧about 15 MBq/kg bw, more preferably of ≧about 20 MBq/kg bw, still more preferably of ≧about 25 MBq/kg bw, still more preferably of ≧about 30 MBq/kg bw and still more preferably of ≧about 35 MBq/kg bw. The RIC may be administered according to known methods, e.g. by infusion.
The RIC of the invention is preferably administered as conditioning regimen in a therapy which comprises additional measures, e.g. administering an antitumor agent, administering an immunosuppressive agent, and/or stem cell transplantation.
Examples of suitable antitumor agents to use in conjunction with RIC include chemotherapeutic agents such as melphalan, cyclophosphamide, (methyl) prednisolone, idarubicin, dexamethasone, etoposide, fludarabine, treosulphan, busulphan (oral or intravenous) alone or combinations of several, e.g. 2, 3, 4 of these agents optionally with bone protecting agents like bisphosphonates. Preferably, the chemotherapeutic agent is high dose melphalan, low dose melphalan or a combination of high dose melphalan or low dose melphalan optionally with other chemotherapeutics such as cyclophosphamide, fludarabine, busulphan and/or treosulphan. Further examples of suitable antitumor agents include antitumor antibodies such as Rituximab.
Examples of suitable immunosuppressive agents include antibodies such as Campath 1H, cyclosporin and rapamycin.
Stem cell transplantation comprises autologous and/or allogeneic stem cell transplantation.
Especially preferred therapeutic protocols, particularly for the therapy of multiple myeloma comprise the steps:                (a) administering an imaging RIC to the patient;        (b) administering a therapeutic RIC to the patient;        (c) administering at least one antitumor agent and/or an antitumor antibody to the patient; and        (d) transplanting autologous or allogeneic stem cells.        
Preferably, step (c) comprises administering melphalan, e.g. high dose melphalan, a combination of fludarabine and antibody Campath 1H optionally with cyclophosphoamide and/or melphalan; cyclophosphamide and busulphan, cyclophosphamide in combination with total body irradiation, and fludarabine in combination with melphalan, busulphan and/or treosulphan. Specific stem cell transplantation conditioning regimens include administration of the following:
Cyclophosphamide 120 mg per m2 and busulphan 16 mg per m2 (or intravenous equivalent); cyclophosphamide 120 mg per m2 and total body irradiation of any total dose, single or fractionated dose delivery; reduced intensity (also know as low intensity, ‘mini-allogeneic transplant’) regimens consisting of combinations of fludarabine and melphalan (doses 110-140 mg per m2), fludarabine plus busulphan 8 mg per m2 (oral or intravenous equivalent), fludarabine plus treosulphan.
Further, the invention shall be explained in more detail by the following examples.